Infection Prevention & Hand Hygiene
A board-focused lesson on infection prevention and hand hygiene, covering ABHR vs soap-and-water rules, the WHO 5 Moments, transmission-based precautions, device-associated HAI bundles, and the QI/systems framing tested on Step 2 CK and Step 3.
Why this is tested
Healthcare-associated infections (HAIs) affect roughly 1 in 31 hospitalized patients on any given day and are a core patient-safety metric. Hand hygiene is the single most effective intervention to prevent HAI transmission, yet baseline compliance is low — which is exactly why it is a favorite QI question. On Step 2 CK / Step 3, items hinge on when to clean hands (WHO's 5 Moments), what agent to use (alcohol-based hand rub vs soap and water), and which precautions a given organism requires.
Every patient gets standard precautions (hand hygiene + PPE matched to anticipated exposure), layered with transmission-based precautions (contact, droplet, airborne) for specific pathogens. Expect next-best-step stems where the right answer is a low-tech systems fix — wash your hands, don an N95, remove the unnecessary catheter — rather than a drug or a test.
- Alcohol-based hand rub (ABHR) is preferred for most clinical hand hygiene — faster, more effective, and gentler on skin than soap. Contains 60–95% alcohol; rub all surfaces until dry (~20 sec).
- Use soap and water (NOT ABHR) when: hands are visibly soiled; after caring for C. difficile or Norovirus; suspected Bacillus anthracis — alcohol does not kill spores and poorly inactivates non-enveloped viruses.
- WHO 5 Moments: (1) before touching a patient, (2) before a clean/aseptic task, (3) after body-fluid exposure risk, (4) after touching a patient, (5) after touching the patient's surroundings.
- Standard precautions apply to every patient: hand hygiene, gloves/gown/mask/eye protection per anticipated exposure, safe sharps handling.
- Gloves are NOT a substitute for hand hygiene — clean hands before donning and after removing gloves.
Transmission-based precautions
| Precaution | PPE & room | Classic pathogens |
|---|---|---|
| Contact | Gown + gloves; private room, dedicated equipment | MRSA, VRE, C. difficile (soap & water!), RSV, scabies, lice, ESBL-producing gram-negatives |
| Droplet | Surgical mask within ~6 ft; private room | Influenza, N. meningitidis, pertussis, mumps, rubella, group A strep |
| Airborne | Fit-tested N95 + negative-pressure (AIIR) room | TB, measles, varicella, disseminated herpes zoster |
- CLABSI (central line): hand hygiene, maximal sterile barrier, chlorhexidine skin prep, avoid femoral site (prefer subclavian), daily review — remove the line when no longer needed.
- CAUTI (Foley): place only for a clear indication, aseptic insertion, maintain a closed drainage system, remove early — avoiding/removing catheters is the #1 lever.
- VAP (ventilator): head of bed 30–45°, daily sedation vacation + spontaneous-breathing/extubation-readiness trial, oral care, DVT + stress-ulcer prophylaxis.
- SSI (surgery): prophylactic antibiotic within 60 min before incision (vancomycin or a fluoroquinolone within 120 min), clippers not razors, glucose control, normothermia.
PPE donning order: gown → mask/respirator → goggles/face shield → gloves. PPE doffing (dirtiest first): gloves → goggles/face shield → gown → mask/respirator (remove the respirator last, outside the room).
Stem: An intern finishes examining a patient with Clostridioides difficile colitis and cleans his hands with alcohol-based hand rub before heading to the next room. A nurse stops him. What is the next best step?
Answer / teaching point:
- Wash with soap and water. Alcohol does not kill C. difficile spores — physical/mechanical washing is required.
- Place the patient on contact precautions: gown + gloves, dedicated equipment, private room.
- Same soap-and-water rule for Norovirus and Bacillus anthracis, and whenever hands are visibly soiled.
- Dx/Tx pearls: confirm with NAAT/PCR (or GDH + toxin EIA); treat with oral vancomycin or fidaxomicin first-line (metronidazole only if the preferred agents are unavailable). Stop the offending antibiotic if possible.
Stem: A 40-year-old man with HIV presents with 3 weeks of cough, night sweats, and weight loss; CXR shows an upper-lobe cavitary infiltrate. What is the next best step in infection control?
Answer / teaching point:
- Airborne precautions immediately: place in a negative-pressure (AIIR) room; everyone entering wears a fit-tested N95 respirator. Then collect 3 sputum specimens for AFB smear and culture (with NAAT).
- Contrast: a droplet organism (e.g., N. meningitidis, influenza) needs only a surgical mask and a standard private room — a surgical mask is NOT sufficient for TB.
- Measles and varicella (and disseminated zoster) also require airborne precautions + N95, not just a mask.
Airborne precautions (fit-tested N95 + AIIR negative-pressure room) — 'MTV':
- M – Measles (rubeola)
- T – Tuberculosis
- V – Varicella (chickenpox); disseminated herpes zoster needs airborne plus contact
Alcohol-resistant → wash with soap & water (scrub, don't just rub):
- *C. difficile* and Bacillus anthracis — form spores that alcohol cannot kill
- Norovirus — a non-enveloped virus that alcohol poorly inactivates (it is not a spore-former)
- Also whenever hands are visibly soiled — mechanical washing removes dirt and organisms
The QI / systems angle (Step 3 favorite)
When a stem asks how to improve or sustain hand-hygiene or infection-control compliance, treat it as a system problem, not individual blame. The high-yield answers emphasize a just culture, easy point-of-care access to ABHR dispensers, and audit-and-feedback of measured compliance rates rather than one-time education.
The landmark example is Pronovost's central-line checklist (the Michigan Keystone ICU project), which standardized the insertion steps and dramatically cut CLABSI rates. The most durable interventions are forcing functions and default changes — e.g., automatic stop-orders that prompt Foley removal — not reminders alone. Favor standardized protocols + measurement and feedback as the sustainable fix.
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